I'm trying to connect to a server (Slack64 13.37) in the US from Italy. The server has been running for a long time, and I was able to connect to it last week from Italy. Now it is giving me this error (full output of ssh -vv pasted below). The http server on the same computer is responding normally. Unfortunately there is no one that can physically access the computer to troubleshoot or restart. I have tried also with a clean .ssh directory.

If I try to access the server with an Android device, it goes so far as to request a password (something it does not do from the Linux client), and then fails with the message java.net.SocketException:recvfrom failed ECONNRESET (Connection reset by peer).

Any idea what could be causing this? Am I screwed until someone can physically access the server?

It's hard to know for sure (without viewing the OpenSSH server logs), but it appears to be deliberately sending you an RST packet. You could easily verify that with tcpdump(8).

At this point - who knows? Could be access control (e.g. TCP wrappers, AllowUsers directive), the OpenSSH server having any number of issues (e.g. due to physical disk, filesystem, permissions problems), or even a marginal network device at some point along the way.

Without 1) physical access; or 2) DRAC / ILOM access, this is going to be tricky to troubleshoot and resolve.